The invention relates to a contaminated surface polishing-washing detergent composition for removing the particles of oxides formed upon working and the particles of removed burrs and cutting metal chips that are left on precision-worked surfaces such as of turbine blades.
The turbine blades are formed, by electrical discharge machining, on the surfaces thereof with a concave-shaped pattern receiving a fluid. At the peripheries of the discharge-machined, concave-shaped pattern, there are left the particles of oxides of an alloy used as a base material and the particles of removed burrs and cutting metal chips. In order to remove the particles of the metal oxides of the alloy and the burrs and the cutting metal chips, it has been usual that polishing-washing is carried out by utilizing a water jet or ultrasonic waves while using a polishing media.
The polishing media is in the form of fine particles and is selected from silica, calcium oxide, aluminium oxide, silicon nitride, silicon carbide, cesium oxide, synthetic or natural diamond, metal silicides, tungsten oxide, titanium nitride, titanium oxide, other types of materials that are harder than an alloy used as a constituent base material for turbine blade, and mixtures thereof.
However, there arise the problems that if a hard polishing media such as of diamond particles is used, the particles may be intruded into the surfaces of the base material for the turbine blade, and that polishing may not proceed satisfactorily when using a relatively soft polishing media.
Further, the particles of metal oxides of an alloy used as a base material for the turbine blade or the particles of removed burrs and the cutting metal chips have substantially the same specific gravity as the polishing media, with the attendant problem that it is difficult to separate the particles of the metal oxides and the particles of the removed burrs and the cutting metal chips from a polishing media solution composition containing the particles of the metal oxides of the alloy and the particles of the removed burrs and cutting metal chips. Further, since the specific gravity of those media is high in respect to water as a fluid, there is the problem that upon making a mixed fluid containing the media, it is difficult to obtain a mixture in which the media keeps mixed uniformly in the long term since the media starts to separate indefinably due to different specific gravity and depending on the rate of the media contained in the mixture.
In the practice of the invention, there is provided a contaminated surface polishing-washing detergent composition using a hard, light RB ceramic and/or CRB ceramic, which composition is re-usable by recycling as a polishing media solution composition after efficient polishing-washing of the surface of a precision-worked base material and removal of the particles of metal oxides and the particles of removed burrs and the cutting metal chips in a simple way from the polishing media solution composition after the polishing-washing by utilizing the difference in specific gravity.
The contaminated surface polishing-washing detergent composition of the invention could solve the above problems, in which an RB ceramic and/or CRB ceramic in the form of a fine power whose bulk specific gravity ranges about 1.25 to 1.35 (gxc2x7cmxe2x88x923) (the bulk specific gravity is measured such that the test piece described in JIS R 1601.4 is subjected to the measuring method of bulk specific gravity described in JIS R 7222.7 and it is to be noted that the RB ceramic and/or CRB ceramic is so porous that only a bulk specific gravity can be measured) is used as a polishing media.
More particularly, the RB ceramic and/or CRB ceramic is porous, has such a hardness that the Vickers"" hardness is about 400 or over, can be divided into a fine powder having a size of approximately 1 xcexcm, is not so hard as diamond and is not thus intruded into an alloy in the surfaces of the base material, and is small in bulk specific gravity. Accordingly, if such a ceramic is dispersed in an aqueous surfactant solution having substantially the same specific gravity to provide a polishing media solution composition, the particles of metal oxides and particles of removed burrs and the cutting metal chips can be settled only by allowing the solution to stand after polishing-washing. The separation of the resultant precipitate by filtration makes it possible to provide a refreshed polishing media solution composition for recycling.
The RB ceramic and CRB ceramic used in the invention are those materials prepared according to the following process.
The porous carbon material that is obtained by using rice bran produced at 900,000 tons per year in Japan and at 33,000,000 tons per year in the world is known according to the studies made by Kazuo Hokkirigawa, one of co-inventors of this application (see xe2x80x9cFunctional Materialsxe2x80x9d May 1997, Vol. 17, No. 5. Pp. 24 to 28).
In this literature, reference is made to a carbon material (hereinafter referred to as RB ceramic) and the preparation thereof, in which the material is obtained by blending and kneading defatted bran derived from rice bran and a thermosetting resin, followed by drying a compact obtained by pressure forming and subsequently baking the dried compact in an atmosphere of an inert gas.
According to this method, the difference in contraction ratio between the size of the pressure formed compact and the size of the final molded compact obtained by baking in the inert gas atmosphere is at 25%, which makes it substantially difficult to make a precise molded compact. A ceramic (CRB ceramic) improved in the ratio has now been developed. The RB ceramic and CRB ceramic individually have the following general properties.
The polishing media used in the invention should comprise fine particles of the RB ceramic and/or CRB ceramic. In the practice of the invention, conventional polishing media may be used in combination.
The polishing media used in combination include silica, calcium oxide, aluminium oxide, silicon nitride, silicon carbide, cesium oxide, synthetic or natural diamond, a metal silicide, tungsten oxide, titanium nitride, titanium oxide, other types of materials that are harder than a base material constituting a body to be worked, and mixtures thereof.
The polishing-washing composition used in the invention can be used for a polishing-washing method using a water jet or ultrasonic waves. Both polishing-washing methods are well known in the art and are not described in detail herein.
With the contaminated surface polishing-washing detergent composition of the invention, when a dispersion medium containing polishing media and obtained after polishing-washing is repeatedly reused, the difference in specific gravity is utilized, and thus, the dispersion medium solution is allowed only to stand, whereupon the particles of metal oxides formed during the course of working and the particles of removed burrs and the cutting metal chips settle from the dispersion medium solution containing the polishing media. The resultant precipitate is removed by a method such as filtration to obtain a fresh polishing media solution composition, which can be recycled.
The polishing media used in combination, such as silica, calcium oxide, aluminium oxide, silicon nitride, silicon carbide, cesium oxide, synthetic or natural diamond, a metal silicide, tungsten oxide, titanium nitride, titanium oxide or the like, cannot be removed only by allowing the solution to stand, and is supplemented in an amount corresponding to that contained in the precipitate, followed by recycling in a similar way.
As is particularly shown in FIG. 1, a polishing media solution composition 2 is pumped up from a storage tank 1, in which the polishing media solution composition 2 is placed, by means of pump 3, and worked portions 6 of a body 5 to be worked are subjected to polishing-washing by means of a water jet gun 4. The polishing media solution composition after the polishing-washing is collected in a temporary storage tank 7 receiving a once treated polishing media solution composition. This is transferred to a standing tank 9 by means of a pump 8. In the standing tank 9, the polishing media solution composition, which contains the particles of metal oxides and the particles of removed burrs and the cutting metal chips formed in the course of the processing over about 1 to 24 hours is allowed to stand. The particles of the metal oxides and the particles of the removed burrs and the cutting metal chips, in most cases, have a specific gravity of approximately 4.0 to 7.0, whereas the bulk specific gravity of the RB ceramic and/or CRB ceramic used as the polishing media of the invention is at approximately 1.3 to 1.4. In addition, the solvent for the polishing media used has a specific gravity of approximately 1.1 to 1.4. Eventually, a precipitate 10 is formed only of the particles of the metal oxides and the particles of the removed burrs and the cutting metal chips. Thereafter, a supernatant liquid portion in the standing tank 9 is recycled, by means of a recycling pump 12, to the storage tank 1 as a polishing media solution composition containing the RB ceramic and/or CRB ceramic that is a polishing media of the invention. It will be noted that the precipitate may be appropriately withdrawn from a precipitate withdrawal port 11.
Furthermore, in another embodiment, there may be used a ultrasonic wave tank 7xe2x80x2 capable of imposing ultrasonic vibrations in place of the water jet gun 4. The polishing media solution composition after having used over a given time in the ultrasonic wave tank 7xe2x80x2 is passed to the standing tank 9 by means of a pump 8xe2x80x2. In the standing tank 9, the polishing media solution composition containing the particles of metal oxides formed in the course of working and the particles of removed burrs and the cutting metal chips is allowed to stand over about 1 to 24 hours, so that the particles of the metal oxides and the particles of the burrs and the cutting metal chips can be separated therefrom.
The RB ceramic and/or CRB ceramic used as the polishing media in the invention should preferably be one which is obtained by baking at relative high temperatures and has a specific gravity of from approximately 1.2 to 1.35.
The solvent used in the invention may be any one which is able to suspend the particles of the polishing media therein, for which water, acids, alcohols and mixtures thereof are preferably used.
Auxiliary additives may be added to the composition containing the polishing media. Potassium chloride, ammonium chloride or a combination thereof may be used as the auxiliary additive, which not only acts to increase the specific gravity of the solution, but also can facilitate the polishing effect of a metal surface with a polishing material.
Moreover, the final pH of the solution can be appropriately adjusted by addition of an acid or a base. The final solution composition can be diluted by adding a solvent to the above parent solution in an amount sufficient to obtain a desired viscosity and a ratio of the solid components. The final ratio of the solid components can be within a range of about 5 to 50 wt %.
In the practice of the invention, surface active agents may be used in order to enhance the dispersability and washing effect. The surface active agents usable in the invention are selected from anionic surface active agents, amphoteric surface active agents, nonionic surface active agents and cationic surface active agents.
Examples of the anionic surface active agent include fatty acid salts such as potassium laurate, potassium myristate, potassium oleate and the like, alkylsulfates such as sodium laurylsulfate, ammonium laurylsulfate, triethanolamine laurylsulfate and the like, alkylbenzenesulfonates such as sodium dodecylbenzenesulfonate, N-acylamino acid salts such as sodium lauroylsarcosine, potassium lauroylsarcosine and the like, alkyl ether carboxylates such as sodium polyoxyethylene tridecyl ether acetate, N-acyltaurine salts such as sodium N-lauroylmethyltaurine, sodium N-cocoylmethyltaurine and the like, N-acylalanine salts such as sodium lauroylmethylalanine, sulfonates such as sodium laurylsulfoacetate, polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene lauryl ether sulfate, triethanolamine polyoxyethylene alkyl ether sulfate and the like, alkanesulfonates such as sodium tetradecanesulfonate, sodium pentadecanesulfonate and the like, xcex1 olefinsulfonates such as sodium tetradecenesulfonate, alkyl phosphates such as sodium laurylphosphate, and polyoxyethylene alkyl ether phosphates such as sodium polyoxyethylene lauryl ether phosphate.
Examples of the amphoteric surface active agent include acetic acid betaine-type agents such as lauryldimethylaminoacetic acid betaine, lauric acid amidopropyldimethylaminoacetic acid betaine and the like, and imidazoline-type agents such as sodium N-coconut oil fatty acid acyl-N-carboxymethyl-N-hydroxyethylethylenediamine.
Examples of the nonionic surface active agent include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, and alkylalkanolamides, and the like. Examples of the cationic surface active agent include alkylammonium salts such as lauryltrimethylammonium chloride, lauryldimethylamine oxide and the like.
The surface active agents not only have stain removability as a detergent, but also enhance the dispersability of the media.
The surface active agent is preferably used in an amount of 0.5 to 6 wt % based on water serving as a dispersion medium. If the amount of a surface active agent is less than 0.5 wt %, detergent power is weak. When the amount exceeds 6 wt %, rinsing properties become worsened. The surface active agents may be used singly or in combination of two or more.
The embodiments of the invention can be summarized as follows.
(1) A polishing-washing composition comprising a polishing media and a dispersion medium, characterized in that at least a part of the polishing media is made of fine powder of an RB ceramic and or CRB ceramic.
(2) A polishing-washing composition as recited in (1) above, wherein the polishing media further comprises, in combination, a fine powder of one or more members selected from the group consisting of silica, calcium oxide, aluminium oxide, silicon nitride, silicon carbide, cesium oxide, synthetic or natural diamond, a metal silicide, tungsten oxide, titanium nitride and titanium oxide.
(3) A polishing-washing composition as recited in (2) above, wherein the ratio by weight of the fine powder of the RB ceramic and/or CRB ceramic to the fine powder of one or more members selected from the group consisting of silica, calcium oxide, aluminium oxide, silicon nitride, silicon carbide, cesium oxide, synthetic or natural diamond, a metal silicide, tungsten oxide, titanium nitride and titanium oxide in the polishing media ranges 30 to 90:70 to 10.
(4) A polishing-washing composition as recited in any one of 1 to 3 above, wherein the fine powder of the RB ceramic and/or CRB ceramic has an average particle size of 1 xcexcm to 1,000 xcexcm.
(5) A polishing-washing composition as recited in any one of 1 to 4 above, wherein the dispersion medium for the polishing media is made of an aqueous dispersion medium containing a surface active agent.
(6) A polishing-washing composition as recited in any one of 1 to 5 above, wherein the dispersion medium for the polishing media comprises potassium chloride, ammonium chloride, sodium sulfate or a combination thereof as an auxiliary additive.
(7) A polishing-washing composition as recited in any one of 1 to 6 above, wherein the dispersion medium for the polishing media has a specific gravity of about 1.1 to 1.4.